Finding sources of pollution across vast supply chains may be one of the largest barriers to eliminating carbon pollution. For some sources like electricity or transportation, it’s relatively easy. But for others like agriculture or consumer electronics, tracing and quantifying greenhouse gas emissions can be a time-consuming, laborious process. It generally takes an expert around three to six months—sometimes more—to come up with an estimate for a single product.

Typically, researchers have to probe vast supply chains, comb the scientific literature, digest reports, and even interview suppliers. They may have to dive into granular details, estimating the footprint of everything from gypsum in drywall to tin solder on circuit boards. Massive databases of reference values offer crude shortcuts, but they can also introduce uncertainty in the estimate because they don’t capture the idiosyncrasies of many companies’ supply chains.